The present invention relates generally to wireless trainable transmitters, particularly for vehicles.
Increasing numbers of new vehicles are being sold with trainable transmitters permanently installed in the vehicle. The trainable transmitters allow consumers to train the transmitter to duplicate an existing transmitter, such as a garage door opener. This approach provides certain advantages. For example, since the transmitter is permanently installed, it is more difficult for a thief to steal the transmitter while obtaining the owner""s address from the glove compartment. Further, the current trainable transmitters pre-store a plurality of cryptographic algorithms allowing the trainable transmitter to be universal. This provides convenience to the consumer by allowing the trainable transmitter to be compatible with many home products, such as garage door openers.
However, a permanently installed trainable transmitter that pre-stores a plurality of cryptographic algorithms suffers from some disadvantages. The universal trainable transmitter, by virtue of its learning capability and pre-storing a plurality of cryptographic algorithms, is simply a universal code grabber. A person with basic electrical/electronic knowledge can increase the range with commercially available RF amplifiers to convert the trainable transmitter to a code grabber. A potential thief could construct such a code grabber and steal codes from a victim""s garage door opener transmitter. Since the universal trainable transmitter pre-stores a plurality of cryptographic algorithms, even advanced rolling codes could be compromised.
Further, current universal trainable transmitters cannot be upgraded to new cryptographic algorithms as the manufacturers of home products (e.g., garage doors, home security entry systems, and wireless switches) change existing codes. Additionally, a universal trainable transmitter would not be compatible with new wireless products by new manufacturers, since there is no common standard for rolling security codes. Since different manufacturers use different codes and encryption algorithms, the universal trainable transmitter cannot be 100% universal or upgradable.
The present invention provides a re-configurable trainable transmitter including a removable plug-in data module which contains a cryptographic algorithm and the other information necessary for generating a wireless signal containing a code associated with a specific security system. The trainable transmitter generally comprises a transmitter and code-generation circuitry, such as a microprocessor. The microprocessor generates a digital code based upon the data in the data module, including the cryptographic algorithm. The microprocessor determines a digital code based upon the cryptographic algorithm and the transmitter generates a wireless signal including the digital code at a frequency also specified by the data module.
Preferably, the data module is associated with a security system from a certain manufacturer or of a specified model or models. Initially, a user would obtain the correct data module necessary to operate the user""s security system, such as garage door opener or home security system, either from the manufacturer of the security system or the manufacturer of the vehicle. By providing the correct plug-in data module, no learning mode would be required. Further, it would not be necessary to store the cryptographic algorithms from the many manufacturers on the trainable transmitter. Only the cryptographic algorithm to be used would be stored on the trainable transmitter.